NOVEL O-D-GALACTURONOYL ESTERS IN THE PECTIC POLYSACCHARIDES OF SUSPENSION-CULTURED PLANT-CELLS
NOVEL O-D-GALACTURONOYL ESTERS IN THE PECTIC POLYSACCHARIDES OF SUSPENSION-CULTURED PLANT-CELLS
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DOI：
10.1104/pp.103.3.993
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发表时间：
1993-11-01
期刊：
影响因子：
7.4
通讯作者：
FRY, SC
中科院分区：
文献类型：
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作者：
BROWN, JA;FRY, SC
Driselase 消化培养菠菜 (Spinacia oleracea L.) 细胞的糖醛酸 6-C-14 标记的初生壁，产生约 18 种新型含糖醛酸化合物，其中大多数可被冷稀碱水解，产生寡聚-[C-14]半乳糖醛酸。一种典型的 Driselase 消化产物（化合物 17）经过非常温和的碱处理后产生 α-(1-->4)-D-[C-14]半乳糖醛三糖 (GalA(3))（在 pH 11 和 25 摄氏度下，7.2 分钟内 GalA(3) 产率达到 50%）。化合物17中的三个半乳糖醛酸残基之一可被硼氢化钠还原为半乳糖残基，这表明GalA残基通过其-COOH基团被酯化为推定的醇。化合物 17 在纸色谱上比 GalA(3) 具有更高的迁移率，表明推定的醇相对非极性。推定的醇不可能是甲醇，因为 Driselase 很容易水解 GalA(3) 的单甲酯、二甲酯和三甲酯，产生游离的半乳糖醛酸。另一种 Driselase 消化产物（化合物 12）是 GalA(3) 的衍生物，显然具有两个非极性酯化取代基：一个与化合物 17 中的不稳定，另一个大约稳定 10 倍。化合物 12 和 17 不能通过体内给予[U-C-14]肉桂酸酯进行标记，这表明它们不是酚类缀合物。通过 Driselase 消化培养的胡萝卜 (Daucus carota L.)、保罗猩红玫瑰 (Rosa sp.) 和高羊茅 (Festuca arundinacea Schreber) 细胞壁，获得类似但色谱可区分的糖醛酸 C-14 标记的酯。在菠菜中，新化合物约占细胞壁半乳糖醛酸残基总量的 5%。观察结果表明，果胶多糖通过 O-D-半乳糖醛酸酯键与初生细胞壁的相对疏水性成分连接。讨论了它们在墙体建筑中可能发挥的作用。
Driselase digestion of uronate-6-C-14-labeled primary walls of cultured spinach (Spinacia oleracea L.) cells yielded about 18 novel uronate-containing compounds, most of which could be hydrolyzed by cold dilute alkali to yield oligo-[C-14]galacturonides. One typical Driselase digestion product (compound 17) yielded alpha-(1-->4)-D-[C-14]galacturonotriose (GalA(3)) upon very mild treatment with alkali (50% yield of GalA(3) in 7.2 min at pH 11 and 25 degrees C). One of the three galacturonate residues in compound 17 was reducible to a galactose residue with sodium borohydride, indicating that that GalA residue was esterified, via its -COOH group, to a putative alcohol. Compound 17 had a higher mobility than GalA(3) on paper chromatography, indicating that the putative alcohol was relatively nonpolar. The putative alcohol could not have been methanol because Driselase readily hydrolyzed mono-, di-, and trimethyl esters of GalA(3) to yield free galacturonic acid. Another Driselase digestion product (compound 12) was a derivative of GalA(3) that apparently possessed two nonpolar esterified substituents: one about as labile as in compound 17, and the other approximately 10 times more stable. Compounds 12 and 17 could not be labeled by in vivo feeding of [U-C-14]cinnamate, suggesting that they were not phenolic conjugates. Similar but chromatographically distinguishable uronate-C-14-labeled esters were obtained by Driselase digestion of walls of cultured carrot (Daucus carota L.), Paul's Scarlet rose (Rosa sp.), and tall fescue (Festuca arundinacea Schreber) cells. In spinach, the novel compounds constituted about 5% of the total galacturonate residues of the cell wall. The observations suggest that pectic polysaccharides are linked, via O-D-galacturonoyl ester bonds, to relatively hydrophobic constituents of the primary cell wall. Their possible role in wall architecture is discussed.